1. Field of the Invention
The present invention relates to a seat structure, and, more particularly, to a seat structure that is adapted to a vehicle.
2. Description of Relevant Art
In general, in a seat for a vehicle, due to a rest and a sound sleep or spaciously making use of a luggage room, it is known that a flat structure which makes a seat cushion and a seat back approximately the same height and horizontal with each other (refer to Japanese Patent Application Laid-Open Publication After Examination No. 7-27239 as a similar art).
This kind of flat structure has a seat cushion and a seat back which each rotate to be in a horizontal reversed state. At reversing, a back face of the seat cushion and a reverse side of the seat back are approximately flush with each other.
Inventors have developed a seat back as follows. A roller provided in a lower end of the seat back engages with a slide rail and an intermediate fulcrum of the seat back is connected to the slide rail or its circumferential member by a back link, so that the seat back is reversed there without a large change of front and rear positions. The roller engages with a lock mechanism, and a normal use state of the seat back is maintained. Then, when the lock mechanism is released, and the roller is slid rearward, the seat back rotates forward, and a horizontal reversed-state is obtained.
However, the seat back can be reversed there, while making use of the roller, the back link, and the lock mechanism. These structures are used only for reversing, and can not be used for another ways. Therefore, for example, an exclusive reclining mechanism is necessary for obtaining a reclining state where a seat back with a flattening structure falls down rearward, and a supporting structure of the seat back is complicated. If a lower end of a seat back is simply rotatably supported without an exclusive reclining mechanism, its rotating fulcrum is fixed at a normal time, and its fixing state is released at a reclining time, the seat back is forcibly fallen down on a back side thereof by its weight at the releasing time, so that operability aspect has a problem.
The present invention has been achieved in view of the conventional art with such points.
It is an object of the present invention to provide a flattening seat structure for a vehicle which has no problem that a seat back is forcibly fallen down to a back side thereof when releasing a fixing state though having a simple structure to rotatably support a lower end of the seatback.
To achieve the object, a first aspect of the invention provides a flattening seat structure for a vehicle which has features as follows. A seat cushion is to pivot to be in a horizontal reversed state and has a back side. A seat back is to pivot to be in a horizontal reversed state and has a reverse side. The reverse side in the horizontal reversed state has a height substantially equal to one of the back side of the seat cushion in the horizontal reversed state. An arm is attached to a lower end of the seat back and supports the lower end of the seat back to be rotated. A roller is fixed to a lower end of the arm and projects outward in a transverse direction of a vehicle body. A slide rail is fixed to a floor and engages with the roller to be slid forward and rearward. A lock mechanism detachably engages with the roller. A back link is connected to an intermediate fulcrum of the seat back above the roller and is connected to one of an intermediate portion of the slide rail and a peripheral member around the portion. A stopper is provided at the lower end of the seat back. The stopper engages with the arm for preventing the arm from rotating. An operating means is for releasing engagement with the stopper and the arm and is provided at an upper part of the seat back. The seat back pivots forward to be in a horizontal reversed state when releasing the lock mechanism and sliding the roller of the seatback rearward. The seat back pivots on the lower end thereof to fall down rearward for a reclining state when releasing engagement with the stopper and the arm.
Preferably, the operating means is at the upper part of the seat back and at the reverse side of the seat back.
Preferably, an upper edge of the arm has an arc shape and is formed with a first notch and a second notch. An end of the stopper is supported by the seat back and another end thereof is formed with a projection directed toward the arm. The projection engages with the first notch in normal usage state of the seat back. The projection engages with the second notch in a position slightly displaced from the normal usage state toward the reclining state.
Preferably, the seat cushion in a normal usage state pivots forward on a front-end fulcrum thereof to be in a horizontal reversed state.
Preferably, the peripheral member has a bracket standing in the vicinity of the slide rail, and the bracket supports an end part of the back link to be pivoted thereon.
According to the invention, the operating means is provided at the upper part of the seat back, and when releasing the stopper and the arm, a hand holds the upper part of the seat back, thus preventing the seat back from falling down rearward with great force. Therefore, in a flatting seat structure, though the seat back is supported to pivot by a simple structure, operability is reliable while reclining.
The operating means is provided at the upper part of the seat back, and the seat back which is falling down rearward is securely supported from the reverse side in operating for releasing, comparing to providing the operating means at a top part of the seat back or a surface thereof. Therefore, the seat back is further sufficiently prevented from falling down rearward with great force.
The second notch is formed in a position slightly displaced from the normal usage state toward the reclining state, and if a hand is detached from the operating means immediately after releasing engagement, the projection of the stopper engages with the second notch halfway, thus to prevent the seat back from falling down to a reclining position with great force.
As a reversed structure of the seat back, the seat back is simply pivoted forward on the front-end fulcrum, and a structure is simple and reversing operation is easy.
An end part of the back link is supported to pivot by the bracket which stands in the vicinity of the slide rail, and manufacturing the slide rail is not necessary for supporting the end part of the back link. Therefore, production of the slide rail is easy and stiffness of the slide rail is prevented from reducing.
A second aspect of the invention provides a seat for a vehicle which has features as follows. There is provided with a guide member. A seat cushion has a first end and a second end. The first end is supported to pivot by the guide member. The seat cushion is to pivot on the first end to be in a first reversed state. A link member has a third end and a fourth end. The third end is supported to pivot by the guide member. A seat back has a fifth end and a sixth end. The fifth end is adjacent to the second end of the seat cushion. The seat back is connected to the fourth end of the link member and is to slide along the guide member at the fifth end thereof to pivot on the fifth end for a second reversed state. The sixth end of the seat back in the second reversed state is approximately flush with the first end of the seat cushion in the first reversed state.
The xe2x80x9ca guide memberxe2x80x9d includes a slide rail and a peripheral member around the slide rail.
Preferably, the seat back has a roller at the fifth end thereof and the roller engages with the guide member for rotating.
Preferably, the seat further has a lock member which is supported to pivot by the guide member and is to latch with the roller to fix the seat back relative to the guide member.
Preferably, the seat back has a seat back body. The seat back has an angle adjusting mechanism for inclining a seat back body at an angle relative to the seat cushion.
Preferably, the seat back body has a seventh end. The angle adjusting mechanism has an arm for supporting the seventh end to be pivoted. The angle adjusting member has a stopper. The stopper is supported to pivot by the seat back body for detachably latching with the arm.